Piezoelectric phonograph pickup with compliant yoke



May 11, 1965 J. c. M ALVAY 3,133,311

PIEZOELECTRIC PHONOGRAPH PICKUP WITH COMPLIANT YQKE Filed Feb. 24. 1959 4 Sheets-Sheet 1 j/reveae v- @ffcw-zzeya May 11, 1965 J. c. MCALVAY 3,183,311

PIEZOELECTRIC PHONOGRAPH PICKUP WITH COMPLIANT YOKE Filed Feb. 24, 1959 4 Sheets-Sheet 2 1 I if? 144 May 11, 1965 J. c. M ALVAY 3,133,311

PIEZOELECTRIC 'PHONOGRAPH PICKUP WITH COMPLIANT YOKE Filed Feb. 24, 1959 4 Sheets-Sheet a &

May 11, 1965 J. c. M ALVAY 3,183,311

PIEZOELECTRIC PHONOGRAPH PICKUP WITH COMPLIANT YOKE 4 Sheets-Sheet 4 Filed Feb. 24, 1959 3/0802" c flue:

United States Patent 3,183,311 PIEZUELECTRHC PHONQGRAPH PICKUP WITH COMPLIANT YUKE John C. McAlvay, Racine, Wis, assignor, by mesne assignments, to Electro-Voice, Incorporated, Buchanan, Mich, a corporation of Indiana Filed Feb. 24, 1959, Ser. No. 795,174- a (Iiairns. (Cl. 179--100.41)

The present invention relates to a transducer and has for its primary object the provision of a new and improved phonograph pickup cartridge. The cartridge of the present invention is intended primarily for use as a binaural or stereophonic pickup, although certain of the features may be utilized with other types of cartridges and the cartridge itself may be converted into another type, such as monaural.

In stereo, an attempt is made to reproduce sounds from two loud-speakers in such a fashion that the effect recreates the original sound source. In the elementary form, the necessary system includes two microphones placed apart and two recording units. The playback system consists of two reproducers, two amplifiers, and two speakers, the speakers being spaced like the microphones in the recording system.

To be effective, the record and playback systems must be entirely separate in behavior, so that a sound from the left of the orchestra (etc) comes from the left speaker only, while a sound from the right comes from the right speaker. Sounds from both sides appear suitably mixed in both speakers.

The characteristic of separate behavior of the right and left hand systems is known as channel separation, and is measured by the comparison of the power level in the undesired channel with the power level in the desired channel. Typical requirements are that the signal in the undesired channel be suppressed at least decibels below the signal in the desired channel, or that only about 4 of the power appear.

One of the most difficult problems in making a suitable pickup cartridge for stereo use is avoidance of generation in the undesired channel. In accordance with the present invention, two expedients are primarily used to reduce this generation, one, involving the construction of the coupling or drive yoke connecting the stylus to the transducer element which reduces the amount of the 45 X 45 components (when the elements are arranged in a 45 X 45 generating system) that are carried to the wrong elements, the other involving the use of structure, such as a wedge, preventing the edgewise bending of the elements by whatever means. These two features of construction complement each other, each contributing to the channel separation.

It should be understood that the energy involved is very tiny, and that it can be supplied by air-borne energy propagated by the vibrations of the needle, or by needle energy coupled back to the transducer elements by the housing structure or other parts of the cartridge.

On the subject of materials desirable for various functions in the cartridge, some elementary functions of the cartridge should be mentioned.

The heart of the cartridge is the transducer or piezo element. This is mounted at one end in the shell by a pair of blocks of elastic nature to provide some cushion to prevent damage and to provide some compliance. The free end of the element is driven by a drive member or yoke from the stylus or needle, the yoke also being elastic in nature, and providing the remainder of the compliance. Substantial compliance is necessary to prevent damage to the record or failure to track due to stiffness. The choice of materials for these members is arbitrary, as is the proportion of compliance provided by yoke vs. the

mounting blocks. These choices are a matter of experience and empirical determination, and always end in a compromise between the output voltage and the compliance. The elastic property mentioned is that tending to restore the material rapidly to its original shape and size.

The materials preferably used for the coupling and wedge, respectively, are polyethylene and highly polymerized polyvinyl chloride, which are characterized by a relatively low hysteresis, so that there is little energy loss in deflecting and restoring the piece.

The stylus and transducer elements are damped against resonating at their natural resonant frequencies by less highly polymerized materials having the property of plastic deformation and high hysteresis. These parts are energy dissipators.

Accordingly, one of the objects of the present invention is to provide a new and improved coupling between the stylus and the transducer element and, more particularly, to provide a coupling of simplified construction providing effective separation between the two components of a binaural transducer so that each transducer element is actuated in response to the desired component of the excursion of the transducer element.

A further object of the present invention is to provide a new and improved coupling for connecting a stylus to a binaural or stereophonic transducer elements, particularly elements arranged divergently with respect to each other relative to a vertical plane to provide a 45 x 45 generating system.

A still further object of the present invention is to provide new and improved coupling means, as set forth in the preceding paragraph, in which the transducer elements are substantially isolated from each other, whereby each of the transducer elements is effectively actuated only by excursions of the stylus in a direction such as to actuate the transducer element.

Another object of the present invention is to provide a new and improved construction in which means are provided to prevent the transducer elements from being vibrated in an undesired (edgewise) direction.

Another aspect of the present invention has to do with an improved construction and mounting of the stylus means whereby it can be made, assembled and operated readily and economically.

Another object of the present invention is to provide a new and improved stylus and stylus supporting and actuating means in which the latter comprises two portions, one to which the stylus or styli are attached and the other constituting a pair of spaced apart bearings resiliently biased away from each other and interconnected by manually operable actuating means or handle constructed in the form of a hairpin bend.

Other objects of the invention have to do with the construction and attachment of journals for the bearing means and detent means for holding the styli in selected operative position.

In brief, the cartridge of the present invention comprises a housing in which are mounted one or two transducer elements. if two transducer elements are used, they are disposed to provide a 45 X 45 generating system, which is accomplished by mounting the elements to diverge downwardly at 45 relative to a vertical axis. One end of each of the transducer elements is relatively fixed with respect to the housing. The other ends are connected to a coupiing element forming one of the important features of the construction. The coupling element is constructed so as to actuate the element or elements in response to a desired component of the excursions of a stylus and to minimize actuation of the elements with respect to undesired excursions. The coupling element used with the binaural arrangement of transducer elements is of resilient low hysteresis (nondissipative) material and generally Y-shaped with the divergent legs connected to the transducer elements and the vertical leg connected to the styli. The divergent legs are provided with apertures so that the transducer elements are connected to the major portion of the coupling by a pair of spaced apart relatively narrow link portions having substantial rigidity in a direction perpendicular to a transducer element of the bender type and which are relatively flexible in a direction parallel to the transducer element. The construction is such that excursion of the stylus tending to move the bender in a direction other than to bend it are minimized, whereas the excursions tending to move it perpendicular to its width are fully effective. Thus, with a 45 X 45 generating system, each of the elements is effectively moved only in response to mutually perpendicular components of the excursions of the stylus. Air borne and random vibrations are prevented from vibrating the transducer elements edgewise by a wedge shaped resilient low hysteresis (nondissipative) pad engaging the edges of the transducer elements, whereby free vibration of the latter is precluded.

The cartridge of the present invention is designed especially for use with a needle assembly comprising two styli selectively used for conventional or long-playing records. The styli are mounted at the end of the needle assembly which may be considered to constitute stylus supporting and actuating means. The latter is composed of two parts, one of which is relatively thin and held by its own resilience against the coupling element and the other of which constitutes a pair of spaced and biased apart thrust bearings which are coaxial relative to each other but the axis of which is at an angle relative to the smaller diameter portion of the stylus holding and actuating means.

The bearings are formed as at the opposite ends of a hairpin-like resilient element constituting a handle, by means of which the position of the styli may be changed selectively to make them operable. Detent means are provided to cooperate with the handle to hold the styli in a desired position. In accordance with one embodiment of the invention, the journal and detents are made as an integral part of the element used to clamp together the two parts of the cartridge housing. The construction is also such that the needle may be readily removed when desired and just as readily reinserted. In accordance with another embodiment of the invention, the journals and detent means are constructed as a part of the housing. In accordance with another feature of the invention, the stylus holding and actuating means, including the handle, is constructed as a unitary element and, furthermore, from a piece of wire of a single diameter.

Further objects and advantages of the present invention will become apparent from the ensuing description of illustrative embodiments of the invention, in the course of which reference is had to the accompanying drawings, in which:

FIGURE 1 is an enlarged bottom plan view of a cartridge constructed in accordance with the present invention shown attached to a tone arm, which is shown but fragmentarily;

FIGURE 2 is a side elevational view of the cartridge of the present invention, it being shown detached from the socket structure in which it is mounted in FIGURE 1;

FIGURE 3 is a fragmentary and considerably enlarged bottom plan view of the cartridge;

FIGURE 4 is a fragmentary vertical cross-sectional view taken along line 4-4 of FIGURE 1 and illustrating details of the socket contact structure;

FIGURE 5 is a vertical cross-sectional view taken along line 5--5 of FIGURE 6;

FIGURE 6 is a side elevational view of the cartridge similar to FIGURE 2, partly broken away better to illustrate the construction;

FIGURE 7 is an enlarged perspective view of the combined cartridge housing holding clip and journal and detent forming structure used in the cartridge;

FIGURE 8 is a vertical transverse cross-sectional view taken along broken line 38 of FIGURE 6;

FIGURE 9 is a fragmentary vertical cross-sectional view taken along line 9-9 of FIGURE 6;

FIGURE 10 is a front elevational view, partly broken away, showing the cartridge of the present invention mounted in a tone arm;

FIGURE 11 is a plan view of a modified form of stylus assembly;

FIGURE 12 is an enlarged vertical cross-sectional view through a modified form of construction in which the detents and journal for the stylus holding and actuating means are formed integrally with the housing;

FIGURE 13 is a horizontal cross-sectional view taken generally along line 13-43 of FIGURE 12;

FIGURE 14 is a vertical cross-sectional view taken along line 14I4 of FIGURE 12;

FIGURE 15 is a front elevational view of a modified form of binaural coupling element; and

FIGURE 16 is a similar view of a monaural coupling element.

Referring now to the drawings, the cartridge of the present invention is illustrated as a whole by reference character 10. The cartridge is shown, in FIGURE 1, mounted on a socket structure 12 mounted in a recess 14 formed at the front end of a tone arm 16. The socket structure 12 is secured as by the rivets 18 to a Phosphor bronze spring leaf secured by screws 22 to bosses 24 formed at the underside of the tone arm. The recess 14 is formed by a top wall 26 and a pair of side walls 28 and front wall 30, all being dependent from the top wall 26. The socket and spring construction are disclosed and claimed in the copending application of Jay L. Johnson, US. application Serial Number 795,106, now abandoned, filed contemporaneously herewith and assigned to the assignee of this application.

The cartridge 10 is shown mounted on the socket structure 12 in FIGURE 1 and it is shown removed from the socket in FIGURE 2 It includes a housing 32 comprising an upper part 32A and a lower part 32B. The two parts of the housing are adhesively secured to each other and securely held by an encircling clamp 34 formlng part of a journal and detent providing clip indicated generally by reference character 36. In the illustrated construction, the cartridge is provided with stylus means taking the form of a pair of styli 40 and 42, one of which is adapted for playing conventional records and the other for long-playing records. The styli are supported by a stylus supporting and actuating means indicated as a whole by reference character 44 and including a portion 46 constituting a handle by means of which the styli are rotated selectively to be placed in position operative to engage an associated record. To facilitate stylus selection, the handle is provided with a small circular finger piece 48, by means of which the handle can be readily moved as from the full line position of FIGURE 1 to the dotted line position. The finger piece may have suitable indicia visible from the top side of the tone arm for indicating which stylus is effective. Additional details of the stylus holding and actuating means will be described later herein after description of the transducer means and the coupling between the latter and the styli.

The transducer means of the present invention, as illustrated, includes two transducer elements 50 and 52, see FIGURE 8, which are mounted to provide what is known as a 45 x 45 generating system. Transducer elements are of the bender type, i.e., they are intended to generate a signal producing voltage when moved at right angles to their width. In the indicated construction, the transducer elements are arranged to diverge downwardly at 45 angles from the vertical. Accordingly, they are disposed at with respect to each other and,

being thus disposed, they are designed for playing binaural or stereophonic records provided, in known manner, with record grooves having components at 90 to each other to provide two record tracks. The transducer elements are coupled at their free ends to the styli by the coupling element indicated as a whole by the reference character 54 and which will be described in greater detail shortly.

Intermediate portions of the transducer elements are relatively fixedly secured to the cartridge housing by damping blocks 56 which are clamped between the upper and lower housing sections when the cartridge is assembled. The mounting blocks may be made of known damping material (high hysteresis) and they may be separated from each other by a dependent partition 32C which is shown in FIGURE 12 in connection with another embodiment of the invention.

The end portions of the transducer elements are relatively fixedly secured in a mounting block 57 also clamped between the housing sections in known manner. The block is provided with split portions 57A giving access to apertures into which the elements extend. The block 57 is best shown in FIGURES 12 and 13 in connection with another embodiment and the split portions are best shown in FIGURE 5.

Returning now to the coupling element 54 which forms one of the principal features of the present invention, it may be noted that in its illustrated form it is generally Y-shaped, see particularly FIGURE 8. The Y- shaped construction provides an effective separation of the two components of the binaural or stereophonic recording. The Y-shape is thus provided by a generally vertical lower portion 60 and the two upwardly extending divergent portions 62 and 64. The latter terminate in generally elliptical portions 66 and 68 which encircle the transducer elements 50 and 52. The dependent portion 60 is provided with a slot '70 including a straight portion 70A and circular portion 7013, the latter of which closely encircles a portion of the stylus holding and actuating means 44, this portion being in the specifically illustrated embodiment being a smaller diameter portion 72 connected to a larger diameter portion 74 in a manner and for a purpose hereinafter to be described in greater detail. The straight portion 70A of the slot enables the stylus holder and coupling element to be assembled and effectively to couple the two together in such manner that the portion 72 of the stylus holder is disposed with its axis at an angle to the axis of the bearings 76 and 78 supporting the portion 74 (see particularly FIGURE 3).

A more efiective separation of the two components in order that each of the respective transducer elements is actuated by the proper record component is provided by making the divergent Y-shapes 62 and 64 in the form of parallel legs or links, a construction which can be readily formed by means of the apertures 62A and 64A in the legs. These apertures and the other parts of the portions, 62 and 64 are such that the links 6213 and 64B of the divergent portions are generally diamond shaped. The advantage of this construction is that, referring to the transducer element St) for example, excursions of the styli in a direction normal to the thickness of the transducer element are effective to move that element, i.e., bend it. Excursions parallel to the thickness are not effective because of the relatively narrow width of the legs 62B and, furthermore, because of the reduced neck portions resulting from the diamond shape of the legs. The result is such that two transducers 5t) and 52 will be actuated primarily by excursions of a stylus in direction normal to their thickness and not by excursions parallel thereto. As a result, there is effective separation of the components of the binaural record. Such separation is obtained but not as eifectively with a Y-shaped construction not having the apertures 62A and 64B.

It should be noted that the isolating linkage is such as to avoid tendency of bending the transducer elements edgewise. Such bending of ceramic elements, which elements 5t and 52 may he, would generate signal voltages. This is undesired and avoided by the present invention.

Edgewise vibration of the transducer elements as a result of vibrations which might be transmitted thereto through the housing or airborne, is prevented by a pad '79 of resilient material, best shown in FIGURES 8 and 12 and engaging the upper edges of the elements. The pad may be cemented to the upper housing section 32A. The pad 79 has a central wedge shaped portion with opposed divergent surfaces 79A engaging the upper edges of the elements. The arrangement is such that the pad exerts somewhat of an edgewise bias against the elements so that they will not vibrate edgewise. This construction also provides a shock absorbing action to prevent damage to the elements as a result of dropping the transducer.

An embodiment of the invention in which separation is effective without the use of apertures and parallel legs is shown in FIGURE 15 to which reference will now be had. In this figure, the coupling element is indicated as a whole by the reference character 80. It comprises an apical portion 82 from which extend the divergent, relatively long legs 84 and 86 disposed at 45 to the vertical and thus at 90 with respect to each other. The legs terminate in ellipitical portions 88 and 9t encircling the transducer elements 5t and 52 respectively. The apical portion is provided with the slot 76 for connection to the stylus holder. If desired, legs 84 and 86 could be provided with openings to provide a more effective separation.

While on the subject of the coupling, it should be noted that either of the two above described constructions could be used for playing monaural records. In order to use the same terminal construction, this can be done by substituting a metal strip for one of the transducer elements. For example, the element 52 could be replaced by a suitable metal strip having oharacteristics corresponding to those of replaced transducer elements.

Another form of monaural coupling that can be used is illustrated in FIGURE 16. The coupling element as a whole is indicated by reference character 92. It comprises a. lower, generally triangular portion 94 provided with the slot 96 for reception of a stylus actuating means. A transducer element 93 is encircled by a generally elliptical portion 1% and the latter is connected to the lower triangular stylus encircling portion 94 by the generally parallel and relatively elongated legs 102 and 1&4. In this embodiment of the invention the transducer element 93 is of the twister type, i.e., it is adapted to be twisted about its central longitudinal axis in response to lateral excursions of a stylus. This construction is particularl useful where a large lateral compliance is desired without greatly affecting the driving efiiciency of a twister type transducer element.

Another of the features of the present invention has to do with the construction of the stylus holding and actuating means 44 and the manner in which it is mounted on the cartridge. Referring now particularly to FIGURES 1 and 2, it will be recalled from the previous description that the stylus holding and actuating means 44 includes the handle 46 and its associated finger piece 48. In the illustrated embodiment, the stylus holding and actuating means is made as a single integral piece including the somewhat smaller diameter portion 72 and the larger diameter portion 74, the latter of which is provided with the thrust bearings 76 and 78 disposed at opposite ends of a resilient hairpin-like portion defining the handle 46. The bearings are received in journals 11d and 112 formed as openings in downwardly extending stamped-out portions or flanges 114 and 116 of the clip 36. The bearing 78 is provided with a small diameter extension or tail 113 which passes through the journal 112 better to insure holding of the parts in assembled relation. Assembly is facilitated by providing the flange 114 with a horizontal slot 129, see FIGURES and 7, through which the smaller diameter portion 72 of the stylus actuating and holding means 44 can be inserted into place. Having slot 120 in a horizontal plane minimizes the possibility of the stylus assembly being moved out of the slot during needle selection. Referring particularly to FIGURE 5, it may be noted that disassembly can be effected by pressing together the two parts of the handle thereby to release bearing 78 and its tail portion from flange 116. Thereafter the other part of the means can be slid out sidewardly through the slot 120. This can be done Without injury to the coupling element 54 which is sufficiently resilient to permit such movement of the stylus actuating and holding means after which the latter can be released from the slot 7t) in the coupling element. Dam ing of the stylus assembly may be effected as by a damping block 122 having a slot 12.4 provided therein so that it can partially at least circle the smaller diameter portion 72 of the stylus holding and actuating means.

The styli are, in accordance with another feature of the present invention, mounted in divergent relation with respect to each other in two different planes. This is done in a simple manner by flattening the outer end portion 72A of the portion 72 and giving it a sort of semicircular configuration as well shown in FIGURE 6. The styli are suitably secured to this portion as by passing them through openings in the flattened portion and securing them to the flattened portion.

The location of the bearing journals is such that the axis of the journals is at an angle relative to the axis of portion 72 of the stylus holding means when the latter is connected to the coupling element. As a result, the resilience of the portion '72 effectively maintains the styli connected to the coupling element and thus to the transducer elements.

The selected stylus is held in desired operating position by detent means associated with the handle 46. The detent means take the form of downwardly extending flanges 126 and 128- having reduced neck portions 130 defining detents 132 so that the two parts of the resilient handle 46 can be held by the detents. In order to prevent movement of the styli beyond the limiting positions flanges 126 and 128 are provided with stops 13 i.

Clip 36 includes also the previously referred to clamp 34 which is constituted by the arms 34A, see particularly FIGURE 7, the free ends of which are bent inwardly, as at 34B, effectively to hold the clamp around the housing and to hold the housing in assembled condition.

Insofar as electrical connections to the transducer elements are concerned, the latter may be connected by flexible terminal strips 141 (see FIGURES 3 and 12) to contacts 142 clipped to the back end of the cartridge housing and adapted to cooperate with contacts 144 having terminals 144A (see FIGURES 1 and 4) of the socket structure. As shown in FIGURE 12, the flexible connectors 146 are separated by a resilient spacer block 146 maintaining the conductors in good electrical contact with the contacts 142.

The socket structure includes the terminals 144A made as integral extensions of contacts 1 4. The latter are clipped onto the socket and have narrower bowed por tions 144B engageable with cartridge contacts 142 when the cartridge is inserted into the socket.

The styli with associated holding and actuating means may be constructed readily. The assembly may be readily attached to and detached from the cartridge. Also the cartridge can be constructed and assembled very easily and held in assembled relation by the clip 36 forrn ing a major component of the device. In operation, the desired stylus for a particular record, either conventional or long palying, is selected by movement of handle 46 to the desired position wherein it is held by one or the other of the detents 132. In playing binaural or stereophonic records, the st lus is moved in such a manner that it has two components of movement at right angles to each other which are more or less perpendicular to the width of the transducers and 52. These movements of the stylus are transmitted to the transducers with effective separation of the components by virtue of tie Y-shaped parallel leg coupling element 54. The pad 79 prevents undesired edgewise vibration of the transducer elements in response to air borne or random vibrations transmitted through the housing.

Relative to the modification of FIGURE 15, the same type of operation takes place so that the element 50 is actuated in response to components of movement normal to its width and the element 52 by components normal to its width and with both relatively unaffected by excursions parallel to their width.

In the modification of FIGURE 16 the transducer element is likewise actuated by the desired component of movement of the stylus.

A modified form of stylus assembly is illustrated in FIGURE 11 to which reference is now had. In this construction, the stylus holding and actuating means, indicated as a whole by reference character 150, is made of wire of uniform diameter having its outer end flattened and configured semicircularly, as indicated by the reference character 152. The styli 40 and 42 are secured to the end portion 152 as in the previously described embodiment. Spaced apart bearings 154 and 156 are formed to be oppositely directed at the ends of the handle defining portion 158. These bearings correspond to the previously described bearings '76 and 78 and may be formed as by swaging or securing small bearings to the wire.

A slightly modified form of cartridge construction is illustrated in FIGURES 12 to 14. In this case the cartridge, indicated as a whole by reference character 160, includes upper and lower housing parts 169A and 160B which are held together by a pair of spaced apart clamping rings 162 and 164. The stylus assembly 44 corresponds to the one previously described, but it is mounted in thrust opposed bearings 166 and 168 formed as by apertures in dependent bosses 170 and 172 formed integrally with the bottom housing section 160B. The detents for holding the handle, which are indicated by the reference characters 174 and 176, are also formed integrally with the lower housing section. The detents are provided with annular grooves 178 in which the handle is resiliently held in selected position. Otherwise the construction is the same as that heretofore described and the major components have been indicated by like reference characters.

While the present invention has been described in connection with illustrative embodiments thereof, it should be understood that details thereof are not intended to be limitative of the invention except insofar as set forth in the accompanying claims.

Having thus described my invention, what I desire to secure by United States Letters Patent is as follows:

1. Transducer apparatus, including in combination, an elongated transducer element adapted to be actuated in a certain direction for generation of signals, stylus means for actuating said element and having a component of movement in said direction, and coupling means between said stylus means and said transducer element comprising a unitary structure of compliant material having spaced parallel elongated portions in a plane lying in said direction, the length of each of said portions in a direction parallel to said plane being substantially greater than the thickness of each portion along an axis normal to said plane, whereby said coupling means i relatively rigid in said plane and has substantially greater compliance in a direction transverse thereto.

2. Transducer apparatus, including in combination, a pair of elongated bender type transducer elements arranged to be bent in planes at right angles to each other for generation of binaural signals, stylus means for actuating said elements having components of movement in said planes, and coupling means between said stylus means and transducer elements comprising a unitary structure having some resilience and including divergent portions arranged at 90 to each other, each divergent'portion having spaced parallel arms constituting a linkage for an associated transducer element and providing rigidity in a direction to bend the associated element and having substantial compliance in a direction at right angles thereto.

3. Transducer apparatus, including in combination, a pair of elongated bender type transducer elements arranged to be bent in planes at right angles to each other for generation of binaural signals, stylus means for actuating said elements having components of movement in said directions, and coupling means between said stylus means and transducer elements comprising a unitary resilient structure including divergent portions arranged at 90 to each other, each divergent portion having spaced parallel generally diamond shaped arms constituting a linkage for an associated transducer element and providing rigidity in a direction to bend the associated element and having substantial compliance in a direction at right angles thereto.

4. Transducer apparatus, including in combination, an elongated twister type transducer element arranged to be twisted along its longitudinal axis for generation of signals, stylus means for actuating said element, and coupling means between said stylus means and transducer element comprising a resilient structure including spaced parallel arms constituting a linkage for twisting the transducer element, said arms being less compliant in a direction to twist the associated element and having more compliance in a direction transverse thereto.

5. Transducer apparatus, including in combination, a pair of flat elongated bender type transducer elements arranged to be bent in planes at right angles to each other for generation of binaural signals, stylus means for actuating said elements having components of movement in said planes, coupling means between said stylus means and transducer elements comprising resilient, nonhysteretic structure including divergent portions arranged at 10 to each other and each having spaced parallel arms constituting a linkage for an associated transducer element and providing rigidity in a direction to bend the associated element and having substantial compliance in a direction at right angles thereto, and resilient, nonhysteretic wedge structure engaging the edges of said elements for opposing edgewise movement thereof.

6. A stereophonic phonograph pickup comprising the elements of claim 1 in combination with a second elongated transducer element adapted to be actuated in a certain direction for generation of signals, means for mounting the first and second generating elements at one end with their axes for generation of signals normal to each other, wherein said unitary structure is provided with spaced parallel elongated portions in a plane lying in said direction for generation of signals in said second elongated transducer element and relatively rigid in said plane and having substantial compliance in a direction transverse thereto, said latter parallel elongated portions coupling the second elongated transducer element to the stylus means.

References Cited by the Examiner UNITED STATES PATENTS 2,742,295 4/ 56 Frederick 179-10041 2,840,644 6/58 Klingener 179-10041 2,848,559 8/58 Palo l79-l00.4l 2,881,005 4/59 Michalko et al. 274-37 2,934,610 4/60 Dieter 179100.41

FOREIGN PATENTS 834,5 72 5/ 60 Great Britain.

OTHER REFERENCES Germany printed application T1 1,092, December 13,

BERNARD KONICK, Acting Primary Examiner.

ROBERT H. ROSE, NEWTON N. LOVEWELL, IRV- ING L. SRAGOW, Examiners. 

3. TRANSDUCER APPARATUS, INCLUDING IN COMBINATION, A PAIR OF ELONGATED BENDER TYPE TRANSDUCER ELEMENTS ARRANGED TO BE BENT IN PLANES AT RIGHT ANGLES TO EACH OTHER FOR GENERATION OF BINAURAL SIGNALS, STYLUS MEANS FOR ACTUATING SAID ELEMENTS HAVING COMPONENTS OF MOVEMENT IN SAID DIRECTIONS, AND COUPLING MEANS BETWEEN SAID STYLUS MEANS AND TRANSDUCER ELEMENTS COMPRISING A UNITARY RESILIENT STRUCTURE INCLUDING DIVERGENT PORTIONS ARRANGED AT 90* TO EACH OTHER, EACH DIVERGENT PORTION HAVING SPACED PARALLEL GENERALLY DIAMOND SHAPED ARMS CONSTITUTING A LINKAGE FOR AN ASSOCIATED TRANSDUCER ELEMENT AND PROVIDING RIGIDITY IN A DIRECTION TO BEND THE ASSOCIATED ELEMENT AND HAVING SUBSTANTIAL COMPLIANCE IN A DIRECTION AT RIGHT ANGLES THERETO. 